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Muscle Denervation (muscle + denervation)

Distribution by Scientific Domains

Medical Sciences	83%

Selected Abstracts

Usefulness of muscle denervation as an MRI sign of peripheral nerve pathology

JOURNAL OF MEDICAL IMAGING AND RADIATION ONCOLOGY, Issue 6 2007
DA Lisle
Summary Peripheral nerve disorders may be classified into compressive or entrapment neuropathies and non-compressive neuropathies. Muscle denervation recognized on MRI may be a useful sign in the diagnosis of peripheral nerve disorders. Acute or subacute denervation results in prolonged T2 relaxation time, producing increased signal in skeletal muscle on short tau inversion-recovery and fat-suppressed T2-weighted images. Chronic denervation produces fatty atrophy of skeletal muscles, resulting in increased muscle signal on T1-weighted images. This review will outline and illustrate the various ways that muscle denervation as seen on MRI may assist in the diagnosis and localization of peripheral nerve disorders. [source]

Denervation hypertrophy may mimic local tumor spread on magnetic resonance imaging

MUSCLE AND NERVE, Issue 1 2006
Carsten Wessig MD
Abstract We report a patient with an extensive paranasal sinus carcinoma. One year after tumor resection, magnetic resonance imaging (MRI) showed swelling of the ipsilateral masticatory muscles with signal increase on T2-weighted images and gadolinium-DTPA uptake, suggestive of local tumor infiltration. However, electromyography, biopsy, and follow-up MRI confirmed denervation pseudohypertrophy of the muscles innervated by the mandibular nerve and excluded tumor recurrence. Muscle denervation and pseudohypertrophy should be considered in the differential diagnosis of appropriate patients with suspected tumor recurrence. Muscle Nerve, 2006 [source]

Time course of changes in angiogenesis-related factors in denervated muscle

ACTA PHYSIOLOGICA, Issue 4 2006
A. Wagatsuma
Abstract Aim:, Denervation leads to capillary regression in skeletal muscle. To gain insight into the regulation of this process, we investigated the time course of changes in capillary supply and gene expression of angiogenesis-related factors during muscle denervation. Method:, Female mice underwent surgery to transect the sciatic nerve, and then the gastrocnemius muscles were isolated at 12 h, 1, 3, 5, 10, 20, or 30 days after surgery. The capillary supply was assessed by immunohistochemistry using anti-PECAM-1/CD31 antibody. The mRNA levels for angiogenesis-related factors were analysed using a real-time polymerase chain reaction. Results:, We found that the capillary-to-fibre ratio began to decrease 10 days after muscle denervation and decreased by 52% after 30 days. The levels of mRNA for vascular endothelial growth factor (VEGF), its receptors [fms-like tyrosine kinase (Flt-1) and a kinase insert domain-containing receptor/fetal liver kinase-1 (KDR/Flk-1)], angiopoietin-1 and angiopoietin-2 of denervated muscle were immediately down-regulated after 12 h and remained lower than control muscle until 30 days after muscle denervation. The levels of mRNA for the VEGF receptor, neuropilin-1, angiopoietin receptor and Tie-2 decreased within 12,24 h, but returned to near those of control muscle after 10,20 days, and again decreased after 30 days. Conclusions:, These findings suggest that denervation-induced capillary regression may be associated with down-regulation of VEGF and angiopoietin signalling. [source]

Usefulness of muscle denervation as an MRI sign of peripheral nerve pathology

Shoulder Disability After Different Selective Neck Dissections (Levels II,IV Versus Levels II,V): A Comparative Study

THE LARYNGOSCOPE, Issue 2 2005
Johnny Cappiello MD
Abstract Objectives/Hypothesis: The objective was to compare the results of clinical and electrophysiological investigations of shoulder function in patients affected by head and neck carcinoma treated with concomitant surgery on the primary and the neck with different selective neck dissections. Study Design: Retrospective study of 40 patients managed at the Department of Otolaryngology, University of Brescia (Brescia, Italy) between January 1999 and December 2001. Methods: Two groups of 20 patients each matched for gender and age were selected according to the type of neck dissection received: patients in group A had selective neck dissection involving clearance of levels II,IV, and patients in group B had clearance of levels II,V. The inclusion criteria were as follows: no preoperative signs of myopathy or neuropathy, no postoperative radiotherapy, and absence of locoregional recurrence. At least 1 year after surgery, patients underwent evaluation of shoulder function by means of a questionnaire, clinical inspection, strength and motion tests, electromyography of the upper trapezius and sternocleidomastoid muscles, and electroneurography of the spinal accessory nerve. Statistical comparisons of the clinical data were obtained using the contingency tables with Fisher's Exact test. Electrophysiological data were analyzed by means of Fisher's Exact test, and electromyography results by Kruskal-Wallis test. Results: A slight strength impairment of the upper limb, slight motor deficit of the shoulder, and shoulder pain were observed in 0%, 5%, and 15% of patients in group A and in 20%, 15%, and 15% of patients in group B, respectively. On inspection, in group B, shoulder droop, shoulder protraction, and scapular flaring were present in 30%, 15%, and 5% of patients, respectively. One patient (5%) in group A showed shoulder droop as the only significant finding. In group B, muscle strength and arm movement impairment were found in 25% of patients, 25% showed limited shoulder flexion, and 50% had abnormalities of shoulder abduction with contralateral head rotation. In contrast, only one patient (5%) in group A presented slight arm abduction impairment. Electromyographic abnormalities were less frequently found in group A than in group B (40% vs. 85% [P = .003]), and the distribution of abnormalities recorded in the upper trapezius muscle and sternocleidomastoid muscle was quite different: 20% and 40% in group A versus 85% and 45% in group B, respectively. Only one case of total upper trapezius muscle denervation was observed in group B. In both groups, electroneurographic data from the side of the neck treated showed a statistically significant increase in latency (P = .001) and decrease in amplitude (P = .008) compared with the contralateral side. There was no significant difference in electroneurographic data from the side with and the side without dissection in either group. Even though a high number of abnormalities was found on electrophysiological testing, only a limited number of patients, mostly in group B, displayed shoulder function disability affecting daily activities. Conclusion: The study data confirm that clearance of the posterior triangle of the neck increases shoulder morbidity. However, subclinical nerve impairment can be observed even after selective neck dissection (levels II,IV) if the submuscular recess is routinely dissected. [source]